WO1999028743A1 - Device for investigating respiratory tract diseases and diagnostic agents - Google Patents

Abstract

The invention relates to a device which can be used in conjunction with a conventional analysis system for diagnosing the metabolic capacity of the respiratory tracts. The device enables specific quantities of suitable diagnostic agents to be added to the inspired air and after a certain time span, can be used to collect metabolites of the diagnostic agents present in the expired air and/or the diagnostic agent itself if still present. Conventional analysis systems are then used to identify the substances which have been expired and collected and determine the quantities present (e.g. using mass spectrometry, gas chromatography, GC-MS-MS, HPL-MS, isotope analysis). Conclusions can then be drawn as to the state of health of the respiratory tract organs. The invention also relates to diagnostic agents which can be used for determining the metabolic capacity of the respiratory tract epithelium, and which are used especially advantageously in conjunction with the inventive device, and to an analytical chemical method for determining the metabolic capacity of the bronchial epithelium.

Description

 Device for the investigation of respiratory diseases and diagnostic

medium

description

The invention relates to a device that can be used in conjunction with a conventional analysis system for diagnosing the metabolic performance of the respiratory organs. With the device, suitable diagnostic agents can be added to the inhaled air in defined amounts and after a certain period of time existing metabolites of the diagnostic agent and / or the still existing diagnostic agent itself can be collected in the exhaled air. With conventional analysis systems (eg using mass spectrometry, gas chromatography, GC-MS-MS, HPLC-MS, isotope analysis), these exhaled and collected substances are identified and quantified, which enables conclusions to be drawn about the state of health of the respiratory organs.

The invention also relates to diagnostic agents which can be used to determine the metabolic rate of the airway epithelium, particularly advantageously also in connection with the device according to the invention, and a corresponding method for chemical-analytical determination of the metabolic rate of the bronchial epithelium. It has long been known from the prior art to collect volatile substances from the exhaled air by passing the air over a sorbent and adsorbing and determining the substances. In the mid-1970s, the so-called tenax, a polymer based on 2,6-diphenyl-p-phenylene oxide, was developed as a particularly suitable sorbent (Krotoszynski et al., J. Chromatogr. Sei. 15., 239- 244, 1977; Krotoszynski et al., J. Analyt. Toxicol. 2, 225-234, 1979).

Recent studies by allace et al. , Environmental Health Perspectives, Vol. 104, Supplement 5, pp. 861-869, 1996 deal with the usefulness of breath analysis in the determination of volatile organic substances in the air after the test persons determined

Chemicals in their environment were exposed

(Car exhaust, petrol stations, swimming pools, exposure to benzene and styrene during active smoking).

Various methods and devices for collecting the volatile and also the non-volatile substances from the breathing air have become known. For example, WO 91/05255 AI describes a method in which non-volatile biopolymers, such as. B. Proteins from the broncho-alveolar boundary fluid, can be detected in the breathing air. For this purpose, breaths are breathed by a test person onto a 1 cm ² sample carrier plate cooled to -196 ° C. The sample is then freeze-dried on the cryotable by applying an ultra high vacuum and then analyzed.

DE 195 05 504 AI describes a method and a device for collecting exhaled breath condensate. Here, the exhaled air flows through a Probensammeiröhr and is cooled therein to a minus temperature below 0 ° C, wherein the liquid and the detachable component ^¬ parts condense and having at a lower temperature than the breath condensate, freeze inner wall of the sample collection tube. Günther Becher et al. describe in Applied

Cardiopulmonary Pathophysiology 5, pp. 215-219, 1995 the determination of leukotriene B ₄ (LTB ₄ ) in the breathing condensate, a mediator that is released from the inflammatory cells into the airways in the event of inflammation of the mucosa. It is shown that the amount of exhaled LTB ₄ with the clinical stage of

Bronchial asthma correlated. The document concludes that the collection of the breath condensate and its biochemical analysis are well suited for the diagnosis of inflammatory airway diseases.

The LTB4 determination is currently the most direct method because it is based on the measurement of a biochemical endogenous component. With this method, however, there is no possibility for a true quantification of the stage of the disease using a standardized one

Reference quantity. On the other hand, a practical application in routine diagnostics is due to the need for

Enrichment and measurement of very small quantities of substances limited, quantities of their intra- and inter-individual

Fluctuations in the normal range can be greater than e.g. the influence of bronchial asthma.

The problem is also that of the mediators occurring in the exhaled air such. B. proteins, peptides, amino acids and phospholipids in the majority is not yet known, as with the disease stage of the airways or lungs correlate so that a diagnosis on this basis is not yet possible. Also in WO 91/05255, which claims a method for diagnosing the state of health of the lungs and the respiratory tract, it is only shown that non-volatile biopolymers can be analyzed in the human breathing air. WO 91/05255 does not show which conclusions can be drawn for the state of health of the respiratory tract and in particular for the metabolic performance of the respiratory epithelium.

All previous solutions lack the fact that they are unable to reliably characterize the physiological-chemical state and the metabolic capacity of the bronchial epithelium via the breathing air.

The object of the invention was therefore to develop a method for determining the state of health of the respiratory tract and in particular the metabolic activity of the cells of the airway interface as well as the surface condition of the bronchial mucosa in a reproducible, reliable, standardized and direct manner by chemical analysis, and to provide a simple device therefor.

According to the invention, a device is provided by means of which a small, precisely defined amount of a suitable diagnostic agent is inhaled during inhalation, and the amount of this agent and / or its metabolites that flows back in during the exhalation is collected and precisely determined by successively defined cooling and adsorption.

A certain proportion of the diagnostic agent is absorbed by the bronchial epithelium and, if necessary, by a biochemical reaction is converted into metabolic products. The extent of absorption and conversion depends on the state of health of the epithelial tissue and thus also on its current metabolic rate. The state of the epithelium can thus be determined in a direct biochemical way, by measuring the proportion of the exhaled diagnostic agent and / or the corresponding proportion of its defined metabolite related to the amount inhaled.

The device according to the invention is designed according to the claims. It consists of a flow channel 1 with a mouthpiece 2 at the front end, an inlet valve 3, an inhalation or injection unit for the diagnostic 4, a cold trap for separating the soluble substances 5 present in the exhaled air, which is arranged at an angle to the flow channel 1 , and an adsorption vessel 6 arranged after the cold trap 5 at the end of the flow channel 1.

In a preferred embodiment of the invention, the longitudinal axis of the cold trap is arranged at an angle of approximately 45 ° to the flow channel, as a result of which an approximately uniform flow through the cold trap is achieved.

The inhalation or injection unit for metering the diagnostic agent into the inhalation air 4 can be designed in different ways, but with devices or device parts known per se. For example, the metering can be carried out with a metering pump or piston syringe or by simply sucking in the diagnostic agent in an appropriate dilution (see Fig. 1). A prior nebulization or atomization of the diagnostic agent is also possible. For example, PC-controlled aerosol production using a compressed air, nozzle or ultrasonic nebulizer or centrifugal atomizer can preferably be used (see Fig. 2). In these cases, the fresh air is drawn in via the inlet valve 3. However, it is not a problem for the person skilled in the art to also provide other suitable inhalation or injection units. For example, a prepared air-diagnostic mixture can also be provided in a reservoir bag and inhaled or metered in via the inlet valve 3 (see Fig. 3).

According to the device of the invention, the exhaled air to be analyzed first flows through the cold trap 5 to collect the metabolites of the diagnostic agent and / or the diagnostic agent still present, in which the water present in the exhaled air is condensed out together with the non-gaseous substances present. The cold trap 5 can, for example, in order to achieve optimal cooling performance, be a reversible cold trap, as shown in FIG. 5. But any other configuration is also possible, the only important thing is that the temperature range that can be set for cooling performance ranges from at least -5 ° C. to -25 ° C. This can be achieved in a very simple manner by means of a cooling jacket tube through which water is passed with a coolant additive. When using a reversible cold trap as shown in Fig. 5, this can be connected to a cooling unit. The cold trap 5 can be arranged so that it can be removed from the device, so that the breath condensate can be collected in the frozen state. But it is also possible with one Computer-controlled design of the device to heat the cold trap 5 after completion of the collection of the exhalate and to suck off the water containing the substances to be determined directly into the analysis unit 12 (see FIG. 4). According to the invention, the device can also contain a plurality of cold traps connected in series.

After the cold trap 5, the gaseous constituents and remaining residues of the exhalate pass through an adsorption vessel 6. The adsorption vessel 6 contains a sorbent which is customary for collecting volatile substances in the exhaled air, e.g. an organic polymer or activated carbon. Basically, however, the breath condensate is deposited on the inner wall of the cold trap 5.

As can be easily recognized by a person skilled in the art, the device can be operated in two different ways, either by means of mechanical valves or by means of a computer-controlled valve circuit. The passive flow control by means of a mechanical valve 3 enables a purely mechanical separation of the inspiratory and expiratory flow path. The smooth-running valve 3 opens at the slightest negative pressure (inspiration) within the mouthpiece, so that the inspired volume always flows through this inlet. As soon as the negative pressure subsides or there is an excess pressure at the mouthpiece (respiratory arrest or exhaled air), the valve closes automatically. The cooling and adsorption section is characterized by its own resistance, which prevents it from flowing in during inspiration. If there are small flow differences (eg measurements on children), a additional passive expiration valve used. When exhaling, there is only the flow path for the exhaled air via the cooling and adsorption section.

As an alternative to the passive variant, when using PC-controlled valves there is the possibility of opening the cooling and adsorption section depending on the expiratory volume and / or flow speed.

The collected breath condensate can thus directly, ie online, by suctioning out the frozen and thawed substances of the analysis unit 12, e.g. B. a conventional combination of chromatograph and mass spectrometer, are supplied. In the case of a removable cold trap 5, the breathing condensate is manually released from the inner wall of the cold trap by thawing and fed to the analysis or kept in the frozen state until measurement. In a particularly preferred embodiment of the invention, the patient is subjected to a cold air provocation known in the diagnosis of respiratory diseases between two examinations, as a result of which a difference measurement for the type and amount of exhaled chemical substances can take place before and after irritation of the mucous membrane. For cold air provocation, a known air cooling device is preferably connected upstream of inlet valve 3, for example the RHES cold air provocation device from Jäger, Wuerzburg. In the device according to the invention, this air cooling device can also be used for cooling the inner tube of the cold trap 5. This difference measurement significantly increases the reliability of the analysis results. The analysis according to the invention of the diagnostic agent still present in the exhalate or its metabolites is carried out using customary analysis methods, depending on the diagnostic agent used, preferably by mass spectrometric and chromatographic examinations.

To ensure that the diagnostic agent is well tolerated, preparations containing the body's own and related substances are preferably used, preferably e.g. Amino acids or higher alcohols in high dilution, as characterized in the claims. These compounds have proven to be suitable diagnostics for the present test method.

In order to ensure a high specificity of the diagnosis and to optimize the sensitivity of the determination, these substances are administered in a stable isotope (i.e.: non-radioactive) labeled form. This is the only way to identify the exhaled diagnostic agent or its specific conversion product as part of the inhaled diagnostic agent.

Thus, it is found in a certain time

Proportion of the stable isotope labeled diagnostic agent

(or its defined secondary product) a reliable measure of the current absorption and metabolic performance of the epithelium.

The invention also relates to the new use of higher, pharmaceutically acceptable alcohols or amino acids in a stable isotope-labeled form for the diagnosis of respiratory diseases and a method for the chemical-analytical determination of the metabolic performance of the bronchial epithelium by means of the device according to the invention. Subjects inhale diagnostics that can form metabolites in the respiratory organs, then the exhaled air is collected and the metabolites and / or the remaining amount of the diagnostic agent are determined after they have been recovered by freezing and adsorption.

In a preferred embodiment variant, a test subject inhales a stabilized isotope labeled higher, pharmaceutically acceptable alcohol as a diagnostic agent. After an exposure time of approx. 1 to 3 hours, preferably 1 to 2 hours, the exhaled air is collected and the exhaled diagnostic agent or its metabolites are frozen out. The amount and / or the isotope content of the substances is then determined and compared with the isotope base value in the subject's breath sample.

Preferred diagnostics are higher alcohols with at least 8 carbon atoms, preferably hexadecanol-1, which is preferably 13C-labeled.

In a further preferred embodiment variant, stable isotope-labeled amino acids are used as diagnostic agents. The exhalation air is collected from the first exhalation process over a period of at least 30 minutes and analyzed according to methods known per se for gaseous metabolites of the diagnostic agent or N-labeled nitrous gases. The preferred diagnostic agent is a ¹⁵ N-labeled amino acid, particularly preferably the amino acid L-arginine. In a further preferred variant, a cold air provocation of the test person is carried out after the exhalation air has been collected and the diagnostic agent is given again for inhalation. The determination of the exhaled air is repeated and these measured values are related to the measured values before the provocation, whereby the sensitivity to the bronchial surface can be determined and also the severity of inflammation can be determined.

The illustrations show:

Fig. 1 Device according to the invention with fresh air valve 3 and simple inhalation or injection unit 4

Fig 2 device according to the invention

Fresh air valve 3 and aerosol inhalation or injection unit 4 Fig. 3 Device according to the invention with an antistatic reservoir bag

Fig. 4 section from the invention

Device with suction device 11, analysis unit 12, cold trap 5 and adsorption section 6

Fig. 5 Reverse cold trap 5

embodiments

example 1

Hexadecanol-1 labeled with the stable isotope ¹³ C (containing more than 95 atomic% ¹³ C in the CH ₂ OH group) is added to 5 L of air in a closed container in defined amounts between 1 and 100 mg. [1- ¹³ C] Hexadecanol used according to the invention as a diagnostic for measuring the permeability of bronchial chienepithels. Before the application of the ¹³ C-hexadecanol-1 preparation, a breath sample of the individual to be examined is collected ("zero sample") in order to measure the current natural ¹³ C base value of the exhaled carbon dioxide. The base value is based on the so-called PDB -Related standard value, which is 1.1112328 atom% ¹³ C. From individual to individual this value deviates from the second value after the decimal point from the standard value, and this deviation can be measured very precisely a mass spectrometer or a special ¹³ C breathing gas measuring device (e.g. the FANci2 device from Fischer Analyze Leipzig).

Then, with 10 breaths, the prepared air-hexadecanol mixture is completely inhaled using the arrangement according to the invention in FIG. 3. After 1 and after 2 hours of waiting, the exhalation air of 50 exhalations each is collected with the arrangement according to the invention. The exhaled [1- ¹³ C] hexadecanol and the carbon dioxide are separated by fractional freezing. The amount and the ¹³ C content of the two substances are determined. The ¹³ C value of the carbon dioxide in the exhaled air now differs characteristically from that of the blank sample: the value is increased the more (eg from 1.11127 to 1, 2467 ... atom% ¹³ C) the more [1- ¹³ C] hexadecanol has penetrated the bronchial epithelium; Because only after crossing this barrier can the hexadecanol get into the bloodstream and be broken down into carbon dioxide in the liver. The amount of the isotope ¹³ C originating from the [1- ¹³ C] hexadecanol and found in the C0 _{2 of} the exhaled air is consequently a reliable measure of the permeability of the bronchial epithelium.

Example 2

The apparatus is used as in Example 1. In addition, however, after the exhalation air has been collected, a cold air provocation is carried out by using a known air cooling device RHES from Jäger, Wuerzburg, which can be connected upstream of valve 3 in the arrangement according to the invention. 20 minutes after the cold air provocation, the steps of admixing, inhaling, exhaling and measuring explained in Example 1 are repeated in the same way. The ¹³ C-carbon dioxide values measured after the cold air provocation are compared to the measured values before the provocation. An intra-individually calibrated and thus inter-individually comparable measure is obtained for the sensitivity of the bronchial surface.

Example 3

Between 1 and 100 mg of a ¹⁵ N solution dissolved in physiological saline are labeled amino acid, preferably L- [guanino-N ₂ ] arginine, admixed. This commercially available ¹⁵ N-labeled arginine contains, for example, 95 atomic% ¹⁵ N in the guanino group. With up to 20 breaths, the prepared air-aerosol mixture with the arrangement according to the invention shown in FIG. 3 is inhaled completely, the exhalation air being guided according to the invention via valve 8 from the first exhalation process over the cold trap and upper adsorbent section, for a total time of 60 minutes, with the cold trap and the adsorber being changed after 30 minutes. After this time, the contents of the cold traps and the adsorber sections are fed to the GC-MS analysis. The substances frozen out together with the exhalation moisture and the adsorbed substances are specifically examined for the gaseous metabolites of [ ¹⁵ N ₂ ] arginine, ie for [ ¹⁵ N] ammonia and ¹⁵ N-labeled nitrous gases. If practically no ¹⁵ N-labeled ammonia or nitrogen oxide was found, the metabolic activity of the bronchial epithelium was normal, ie relatively low. In contrast, the metabolic activity is greatly increased in the stress or inflammation state. This manifests itself in a comparatively large amount of ^1B N-labeled gaseous substances in the exhalation condensate, which can only come from the ¹⁵ N-labeled arginine. The amount of ¹⁵ N isotope found in the condensate is therefore a reliable measure of the metabolic activity and the degree of inflammation of the bronchial epithelium. In addition, the urine can also be examined for ¹⁵ N-containing metabolites. Example 4

The apparatus is used as in Example 3. After the one-hour collection of exhalation condensate and ^ls N-labeled gases, a cold air provocation takes place in a manner known per se as in Example 2. This allows the sensitivity of the bronchial epithelium to a cold air provocation to be measured biochemically for the first time - noninvasively and in vivo in the form of a reduced one or increased amino acid metabolism. The severity of the inflammation can also be determined from the ratio of the ¹⁵ N amounts of the exhaled gases from the inhaled arginine before and after the cold air provocation.

Reference list

Fig. 1

1 flow channel

2 mouthpiece

3 inlet valve for

Fresh air

4 inhalation or injection unit

4a supply line

4b Vessel for diagnostics

4c valve

5 cold trap

6 absorption vessel

7 flow meter

8 valve

10 Computer control

Fig. 2

1 flow channel

2 mouthpiece

3 inlet valve for fresh air

4 inhalation or injection unit

4a supply line

4b Vessel for diagnostics

4c valve

4d nebulizer for the diagnostic

5 cold trap

6 absorption vessel

7 flow meter

8 valve

10 computer control

11 suction device

12 analysis unit Fig. 3

1 flow channel

2 mouthpiece 3 inlet valve for air-diagnostic mixture

4 reservoir bags with air-diagnostic mixture

5 cold trap

6 absorption vessel

7 flow meter 8 valve

10 computer control

11 suction device

12 analysis unit

Fig. 4

1 flow channel

5 cold trap

6 absorption vessel 11 suction device

12 analysis unit

Fig.

l flow channel

5 cold trap

13 inner tube

14 outer body with cooling fins

Claims

claims 1. A device for examination of respiratory ^¬ diseases by metering diagnostic agents for respiratory air, which can form in the respiratory organs, metabolites, and collecting in the Ausat ^¬ mung air existing substances consisting of a flow channel (1) with a mouthpiece (2) at the front end, an inlet valve (3), an inhalation or injection unit for the diagnostic (4), a cold trap for separating the substances (5) present in the exhaled air, which is arranged at an angle to the flow channel (1), and one after the cold trap (5) at the end of the flow channel (1) arranged adsorption vessel (6). 2. Device according to claim 1, characterized in that the inhalation or injection unit (4) comprises a feed line (4a), a vessel for the diagnostic agent (4b) and a valve (4c) and the inlet valve (3) is an inlet valve for fresh air is. 3. Apparatus according to claim 1 or 2, characterized in that the inhalation or injection unit (4) Contains nebulizer (4d) and the inlet valve (3) is an inlet valve for fresh air. 4. The device according to claim 1, characterized in that the inhalation or injection unit (4) is a reservoir bag with a prepared air-diagnostic mixture, which is connected to the flow channel (1) via the inlet valve (3). 5. Device according to one of claims 1 to 3, characterized in that a cold air provocation device is connected upstream of the inlet valve (3). 6. Device according to one of claims 1 to 5, characterized in that it is designed under computer control. 7. Device according to one of claims 1 to 6, characterized in that a flow meter (7) is arranged in the flow channel (1). 8. Apparatus according to claim 6 or 7, characterized in that a suction device (11) is arranged in the flow channel (1) in front of the cold trap (5). 9. The device according to claim 8, characterized in that the suction device (11) is connected to an analysis unit (12). 10. Diagnostic agent for inhalation to determine the state of health of the respiratory tract, comprising stabilized isotope labeled higher, pharmaceutically acceptable alcohols and, where appropriate, customary pharmaceutical additives. 11. Diagnostic agent according to claim 10, characterized in that the higher alcohols are at least C ₈ alcohols. 12. Diagnostic agent according to claim 10 or 11, characterized in that the higher alcohols ^{! 3 are} C-labeled. 13. Diagnostic agent according to one of claims 10-12, characterized in that the stable isotope labeled higher alcohol is ¹³ C-labeled hexadecanol -1. 14. Diagnostic agent for inhalation to determine the state of health of the respiratory organs, comprising stabilized isotope-labeled amino acids and optionally pharmaceutically acceptable additives. 15. Diagnostic agent according to claim 14, characterized in that the amino acids are ¹⁵ N- labeled. 16. Diagnostic agent according to claim 14 or 15, characterized in that the amino acid is L-arginine. 17. Use of stabilized isotope-labeled higher, pharmaceutically acceptable alcohols or stabilized isotope-labeled amino acids for determining the state of health of the respiratory organs, these compounds being inhaled. 18. A method for determining the metabolic performance of the bronchial epithelium, characterized in that by means of the device according to one of claims 1 to 9 of a subject's breathing air diagnostics which can form metabolites in the respiratory organs are metered in, then those in the Exhaled air substances are collected and the metabolites and / or the remaining amount of the diagnostic agent are analyzed.